gistfile1

"""
    What I'm trying to do is draw a border around my widget.
    Here, an AsyncImage.
"""
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.gridlayout import GridLayout
from kivy.uix.tabbedpanel import TabbedPanel

Builder.load_string("""
<TestWidget>
    default_tab_content: normal_panel
    default_tab_text: "Normal"

    TabbedPanel:
        id: normal_panel
        default_tab_content: first_tab
        tab_pos: "top_mid"
        pos_hint: { "center_x": .5, "center_y": .5}
    
        GridLayout:
            id: first_tab
            cols: 2
    
            canvas:
                Color:
                    rgb: 0, .20, .30
                Rectangle:
                    size: self.size
                    pos: self.pos
    
            Label:
                text: "Let's"
                font_size: 20
                size_hint_y: None
                height: 40
    
            Label:
                text: "Go"
                font_size: 20
                size_hint_y: None
                height: 40
    
            AsyncImage:
                source: "http://mike.majerti.fr/2.png"
                allow_stretch: True
    
                canvas.after:
                    Color:
                        rgb: 0, .5, 0
                    Line:
                        points: self.pos[0], self.pos[1], self.pos[0], self.size[1]
                    Line:
                        points: self.pos[0], self.pos[1], self.size[0], self.pos[1]
                    Line:
                        points: self.size[0], self.pos[1], self.size[0], self.size[1]
                    Line:
                        points: self.pos[0], self.size[1], self.size[0], self.size[1]
    
            Label:
                text: "The mall"
                font_size: 20

    TabbedPanelHeader:
        text: "Weird"
        content: weird_panel

    TabbedPanel:
        id: weird_panel
        default_tab_content: weird_tab
        tab_pos: "bottom_mid"
        tab_height: 100
        pos_hint: { "center_x": .5, "center_y": .5}
    
        GridLayout:
            id: weird_tab
            cols: 2
    
            canvas:
                Color:
                    rgb: 0, .20, .30
                Rectangle:
                    size: self.size
                    pos: self.pos
    
            Label:
                text: "Let's"
                font_size: 20
                size_hint_y: None
                height: 40
    
            Label:
                text: "Go"
                font_size: 20
                size_hint_y: None
                height: 40
    
            AsyncImage:
                source: "http://mike.majerti.fr/2.png"
                allow_stretch: True
    
                canvas.after:
                    Color:
                        rgb: 1, 0, 0
                    Line:
                        points: self.pos[0], self.pos[1], self.pos[0], self.size[1]
                    Line:
                        points: self.pos[0], self.pos[1], self.size[0], self.pos[1]
                    Line:
                        points: self.size[0], self.pos[1], self.size[0], self.size[1]
                    Line:
                        points: self.pos[0], self.size[1], self.size[0], self.size[1]
    
            Label:
                text: "The mall"
                font_size: 20

    TabbedPanelHeader:
        text: "Weirder"
        content: weirder_panel

    TabbedPanel:
        id: weirder_panel
        default_tab_content: weirder_tab
        tab_pos: "bottom_mid"
        tab_height: 100
        size_hint: .8, .8
        pos_hint: { "center_x": .5, "center_y": .5}
    
        GridLayout:
            id: weirder_tab
            cols: 2
    
            canvas:
                Color:
                    rgb: 0, .20, .30
                Rectangle:
                    size: self.size
                    pos: self.pos
    
            Label:
                text: "Let's"
                font_size: 20
                size_hint_y: None
                height: 40
    
            Label:
                text: "Go"
                font_size: 20
                size_hint_y: None
                height: 40
    
            AsyncImage:
                source: "http://mike.majerti.fr/2.png"
                allow_stretch: True
    
                canvas.after:
                    Color:
                        rgb: 1, 0, 0
                    Line:
                        points: self.pos[0], self.pos[1], self.pos[0], self.size[1]
                    Line:
                        points: self.pos[0], self.pos[1], self.size[0], self.pos[1]
                    Line:
                        points: self.size[0], self.pos[1], self.size[0], self.size[1]
                    Line:
                        points: self.pos[0], self.size[1], self.size[0], self.size[1]
    
            Label:
                text: "The mall"
                font_size: 20
""")

class TestWidget(TabbedPanel):
    pass

class TestApp(App):

    def build(self):
        widget = TestWidget()
        return widget

if __name__ == "__main__":
    TestApp().run()